Deletes/Updates 
Delete selectivity <percentage>%: <number of> deletes, <number of> rows read, <number of> rows qualified
Update selectivity <percentage>%: <number of> updates, <number of> rows read, <number of> rows qualified
The ratio of read rows to modified rows is poor for DELETE or UPDATE statements.
Before UPDATE and DELETE statements can modify or delete rows, the row must be localized in the table. The same access strategies are used as in a SELECT statement.
Find the statement that causes this poor ratio of read rows to found rows, and check the access strategies for this statement.

For information on creating optimized SQL
statements, see
Optimizer:
SAP DB 7.4..